Alt-J have debuted a pioneering new piece of gig technology that aims to stop people recording shows on their phones.

Following their album award win at the Ivor Novellos on Thursday, the band became the first act to utilise the Soundhalo video app at their Brixton Academy show, allowing fans to download tracks to their smartphones immediately after they were performed. It's hoped the new app will deter audiences from holding their phones in the air to record tracks at gigs – a practise Yeah Yeah Yeahs recently banned.

The beta version of Soundhalo launched on Android platforms on Thursday and will soon be made available elsewhere. A production crew at the venue combines footage with audio taken directly from the sound desk and delivers a fully mixed and mastered video MP4 straight to a cloud directly after the song has finished. Fans can then pay to download the files, one song at a time. The app is available via soundhalo.com.

Alt-J's drummer, Thom Green, said: "I think it's amazing that the whole show was streamed live on the internet. I'm glad they chose us to kick the whole thing off, it's a real honour. It's one of those things that you can't really believe doesn't already exist, it's just so perfect. I can't wait to see how far it goes and to watch it back myself and watch my own highlights on my phone."

The band can now add the Ivor Novello to the Mercury prize already won by their acclaimed album An Awesome Wave. And Green said that the latest win was even sweeter. "We've probably had the best day in our career so far," he said. "And it was overwhelming almost to play to that amount of people; it felt really special. When I look at the four of us together it's quite emotional actually and I'm just really proud of us. Joe lost his voice today and I really felt for him when he started singing – everything suddenly really hit home. The crowd's response to Joe, singing with him and supporting him through, was amazing. It's just a very, very proud day."